/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: RelationalExpr.java,v 1.2.4.1 2005/09/12 11:05:00 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.generic.BranchInstruction;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.INVOKESTATIC;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.PUSH;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.BooleanType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.IntType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeSetType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.RealType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ReferenceType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ResultTreeType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
import com.sun.org.apache.xalan.internal.xsltc.runtime.Operators;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 */
final class RelationalExpr extends Expression {

  private int _op;
  private Expression _left, _right;

  public RelationalExpr(int op, Expression left, Expression right) {
    _op = op;
    (_left = left).setParent(this);
    (_right = right).setParent(this);
  }

  public void setParser(Parser parser) {
    super.setParser(parser);
    _left.setParser(parser);
    _right.setParser(parser);
  }

  /**
   * Returns true if this expressions contains a call to position(). This is
   * needed for context changes in node steps containing multiple predicates.
   */
  public boolean hasPositionCall() {
    if (_left.hasPositionCall()) {
      return true;
    }
    if (_right.hasPositionCall()) {
      return true;
    }
    return false;
  }

  /**
   * Returns true if this expressions contains a call to last()
   */
  public boolean hasLastCall() {
    return (_left.hasLastCall() || _right.hasLastCall());
  }

  public boolean hasReferenceArgs() {
    return _left.getType() instanceof ReferenceType ||
        _right.getType() instanceof ReferenceType;
  }

  public boolean hasNodeArgs() {
    return _left.getType() instanceof NodeType ||
        _right.getType() instanceof NodeType;
  }

  public boolean hasNodeSetArgs() {
    return _left.getType() instanceof NodeSetType ||
        _right.getType() instanceof NodeSetType;
  }

  public Type typeCheck(SymbolTable stable) throws TypeCheckError {
    Type tleft = _left.typeCheck(stable);
    Type tright = _right.typeCheck(stable);

    //bug fix # 2838, cast to reals if both are result tree fragments
    if (tleft instanceof ResultTreeType &&
        tright instanceof ResultTreeType) {
      _right = new CastExpr(_right, Type.Real);
      _left = new CastExpr(_left, Type.Real);
      return _type = Type.Boolean;
    }

    // If one is of reference type, then convert the other too
    if (hasReferenceArgs()) {
      Type type = null;
      Type typeL = null;
      Type typeR = null;
      if (tleft instanceof ReferenceType) {
        if (_left instanceof VariableRefBase) {
          VariableRefBase ref = (VariableRefBase) _left;
          VariableBase var = ref.getVariable();
          typeL = var.getType();
        }
      }
      if (tright instanceof ReferenceType) {
        if (_right instanceof VariableRefBase) {
          VariableRefBase ref = (VariableRefBase) _right;
          VariableBase var = ref.getVariable();
          typeR = var.getType();
        }
      }
      // bug fix # 2838
      if (typeL == null) {
        type = typeR;
      } else if (typeR == null) {
        type = typeL;
      } else {
        type = Type.Real;
      }
      if (type == null) {
        type = Type.Real;
      }

      _right = new CastExpr(_right, type);
      _left = new CastExpr(_left, type);
      return _type = Type.Boolean;
    }

    if (hasNodeSetArgs()) {
      // Ensure that the node-set is the left argument
      if (tright instanceof NodeSetType) {
        final Expression temp = _right;
        _right = _left;
        _left = temp;
        _op = (_op == Operators.GT) ? Operators.LT :
            (_op == Operators.LT) ? Operators.GT :
                (_op == Operators.GE) ? Operators.LE : Operators.GE;
        tright = _right.getType();
      }

      // Promote nodes to node sets
      if (tright instanceof NodeType) {
        _right = new CastExpr(_right, Type.NodeSet);
      }
      // Promote integer to doubles to have fewer compares
      if (tright instanceof IntType) {
        _right = new CastExpr(_right, Type.Real);
      }
      // Promote result-trees to strings
      if (tright instanceof ResultTreeType) {
        _right = new CastExpr(_right, Type.String);
      }
      return _type = Type.Boolean;
    }

    // In the node-boolean case, convert node to boolean first
    if (hasNodeArgs()) {
      if (tleft instanceof BooleanType) {
        _right = new CastExpr(_right, Type.Boolean);
        tright = Type.Boolean;
      }
      if (tright instanceof BooleanType) {
        _left = new CastExpr(_left, Type.Boolean);
        tleft = Type.Boolean;
      }
    }

    // Lookup the table of primops to find the best match
    MethodType ptype = lookupPrimop(stable, Operators.getOpNames(_op),
        new MethodType(Type.Void, tleft, tright));

    if (ptype != null) {
      Type arg1 = (Type) ptype.argsType().elementAt(0);
      if (!arg1.identicalTo(tleft)) {
        _left = new CastExpr(_left, arg1);
      }
      Type arg2 = (Type) ptype.argsType().elementAt(1);
      if (!arg2.identicalTo(tright)) {
        _right = new CastExpr(_right, arg1);
      }
      return _type = ptype.resultType();
    }
    throw new TypeCheckError(this);
  }

  public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
    if (hasNodeSetArgs() || hasReferenceArgs()) {
      final ConstantPoolGen cpg = classGen.getConstantPool();
      final InstructionList il = methodGen.getInstructionList();

      // Call compare() from the BasisLibrary
      _left.translate(classGen, methodGen);
      _left.startIterator(classGen, methodGen);
      _right.translate(classGen, methodGen);
      _right.startIterator(classGen, methodGen);

      il.append(new PUSH(cpg, _op));
      il.append(methodGen.loadDOM());

      int index = cpg.addMethodref(BASIS_LIBRARY_CLASS, "compare",
          "("
              + _left.getType().toSignature()
              + _right.getType().toSignature()
              + "I"
              + DOM_INTF_SIG
              + ")Z");
      il.append(new INVOKESTATIC(index));
    } else {
      translateDesynthesized(classGen, methodGen);
      synthesize(classGen, methodGen);
    }
  }

  public void translateDesynthesized(ClassGenerator classGen,
      MethodGenerator methodGen) {
    if (hasNodeSetArgs() || hasReferenceArgs()) {
      translate(classGen, methodGen);
      desynthesize(classGen, methodGen);
    } else {
      BranchInstruction bi = null;
      final InstructionList il = methodGen.getInstructionList();

      _left.translate(classGen, methodGen);
      _right.translate(classGen, methodGen);

      // TODO: optimize if one of the args is 0

      boolean tozero = false;
      Type tleft = _left.getType();

      if (tleft instanceof RealType) {
        il.append(tleft.CMP(_op == Operators.LT || _op == Operators.LE));
        tleft = Type.Int;
        tozero = true;
      }

      switch (_op) {
        case Operators.LT:
          bi = tleft.GE(tozero);
          break;

        case Operators.GT:
          bi = tleft.LE(tozero);
          break;

        case Operators.LE:
          bi = tleft.GT(tozero);
          break;

        case Operators.GE:
          bi = tleft.LT(tozero);
          break;

        default:
          ErrorMsg msg = new ErrorMsg(ErrorMsg.ILLEGAL_RELAT_OP_ERR, this);
          getParser().reportError(Constants.FATAL, msg);
      }

      _falseList.add(il.append(bi));              // must be backpatched
    }
  }

  public String toString() {
    return Operators.getOpNames(_op) + '(' + _left + ", " + _right + ')';
  }
}
